I will sign in my contract with Starbucks on Monday, will be working part time.

As an international student, my parents want me back home this July while I will be having my summer holiday.

I don't want to lose my job, but then is asking for 2-3 weeks holiday alright or is there high possibility that I will get replaced since during summer vacation period, there will be more tourists and coffee shops will get busier than normally so they might need to employ someone else?